Valve-gear for steam-engines.



PATENTEEMAY 19,1903..-

E. L. CAMPBELL. A VALVE GEAR EUR STEAM ENGINES.

APPLIoATIoN FILED DEG. 8.1902.

2 SHEETS-SHEET 1.

No MQDEL.

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QPATENTED MAY 19, 1903.

B.. L. CAMPBELL." VALVE GEAR EUR STEAM ENGINES.

APPLIOATION .FILED DEG. 8, 1902.

SHEETS-SHEET' 2- N0 MODEL.

TH: mums PETERS co, Puouumo.. wAsmNGroN. u. c.

y UNITED `ST Patentedll/Iay 19, 1903.

PATEN T OFFICE.

BoBER'r LEON CAMPBELL, oF TUsKEeEE, ALABAMA, AssIGNoBoEoNE- HALE To BooIIEB T. WASHINGTON, oE TUsKEeEE, ALABAMA.

VALVE-GEAR FOR lSTEAM-ENGINES.

2APEGIFICA'IION forming part of Letters Patent No. 728,364, dated May 19, 1903.

Application iiled December 8, 1902. Serial No.1l34,353. (No model.)

To @ZZ whom it may concern:

Be it known that I, ROBERT LEON CAM?- lBELL, a citizen of the United States, residing at Tuskegee, Alabama, have invented certain new and useful Improvementsin Valve-Gear for Steam-Engines, of which the following is a specification.

My invention relates to improvements inreversing valve-gear forstationary, locomotive,-

and marine engines.

My object is to provide a simple and efcient construction whereby theT direction of the engine may be changed with a minimum amount of friction and as good results secured with a single eccentric as are ordinarily accomplished by two.

The invention is illustrated in the accompanying drawings, in which- Figure l is an elevation showingttheimproved valve-gear applied to a stationary engine of the vertical type. Fig. 2 is a sectional elevation. y

Referring by reference-letters totheseviigf ures, H designates a link of substantiallythe ordinary form, which is centrally pivoted at O and has one end connected by a rodK and strap K with the eccentric R, secured to the crank-shaft Q. y. G designates a cross-bar which is rigidly secured to the cross-head G of the engine-bysuitable means, such as a screw M. A link D is connected at one end tovthis cross-bar G by a screw E, while the opposite end of said link D is connected by a screwk P with the outer end of a lever-arm A; Y The inner end of the lever-arm A is connected by screw-pin C with the valve-rod S.- @j

A rod F has one end pivotally connected with the arm A at a suitable distance from the pivot C, while its opposite end is `connected to the block which slides in the Vlink H. N designates the shifting link, whichis connected at one end, as shown, to the lower end of the rod F, while'its opposite end is pivotally connected at L to the shifting-lever V, the position of which is controlledin-the ordinary manner by pawl T engaging segment T', `and operated by lever V and connecting-rod Vj By the above construction it will be seen that I provide an extremely simple and efcient form of valve-gear in which all neceslengthened, and vice versa.

saryl results are secured by the use of a single eccentric.

It will be noticed that the eccentric is set on the shaft at an angle of ninety degrees with 'the wrist or crank pin, which cause the valve to close theports too quickly for practical use unless sonne provision is made to arrest the movement ofthe valve 'at the proper` time. In lever A, connecting-rod D, and cross-bar G,

"connected to each other and to the cross-head,

I have -the arrangement that will cause the valve to close or open the ports at any desired portion of the stroke, which can be arranged by.. lengthening or shortening the stroke of the eccentric and shortening andlengthening the stroke of the lever arrangement. When the stroke of the eccentric is shortened, ythe stroke of the lever must be Thus I have ail arrangement that is simple and practical. v Having thus described my invention, what I claimis' 1.,'In a reversing valve-gear .for steam-engines asing'le eccentric,:a rocking link hav,- ing one end connected with the eccentric, a lever-arm having one end pivotally connected to the valve-rod, a direct connection between the other end of said lever-arm and the crosshead whereby the said other end and pistonrod move iny unison, and a rod having one end pivotallylconnected to the lever-arm and forming a fulcrum therefor, and its other end adj ustably connected to the rockin glink, substantially as described. 2. AIn a reversing 'valve-gear for steam-,engines, a single eccentric, a rocking link having one end fconnectedthereto, a cross-arm4 mounted to move in' unison with the piston- S. B. THOMAS, E. J. JONES. 

